Relay timing circuits and systems



- 5, 1939- R. E. MARBURY RELAY TIMING CIRCUITS AND SYSTEMS Filed Nov. 24, 1937 2 Sheets-Sheet 1 I INVENTOR F442; 5. Maria/7y ATT RNEY WITNESSES:

Dec. 5, 1939. R. E. MARBURY 2,182,637

RELAY TIMING CIRCUITS AND SYSTEMS Filed NOV. 24, 1937 2 Sheets-Sheet 2 7=6 -7=7 wlTuEsszi .5 INVENTOR aim r R449 5 Narbwy,

ATTORNEY Patented Dec. 5, 1939 UNITED STATES PATENT OFFICE RELAY TIliflNG CIRCUITS AND SYSTEMS Pennsylvania Application November 24, 1937, Serial No. 176,251

4 Claims.

This invention relates to relays and particularly to relay systems including fundamental electrical elements having time constants so related to the time constants of the relay winding I or windings as to establish a desired time interval of operation for the relay, either in its forward or actuating operation, or in its backward or resetting operation.

An object of my invention is to provide a relay 10 system embodying a combination of elements having time constants cooperatively related to those of the relay to establish a predetermined type of desired time operation and a predetermined type of desired time of resetting of the 15 relay.

In electrical systems it is frequently desirable to control the time element in the actuating operation of a relay, to operate a switch, or in the resetting operation of the relay to perform the 50 reverse operation of the switch, for the purpose of controlling an external circuit or an operation in a sequence of control. There are several types of timing operations frequently desired in a relay. One type of operation that may be desired is a delayed actuating or closing operation of the relay, and a delayed resetting or opening operation of the relay.

Another type of operation frequently desired is a quick actuating or closing operation of the relay, and a delayed resetting or opening operation of the relay.

A third type of operation frequently desired is that in which a fixed minimum time interval shall elapse between successive operations of a 35 relay.

I have illustrated several relay circuits, respectively including a combination of fundamental electrical elements arranged to have electrical circuit constants cooperatively related to the 40 electrical constants of the relay winding in such manner as to establish, purely electrically, the timing interval desired for the actuating or closing operation of the relay, or the timing interval desired for the resetting 'or opening interval of the relay.

Various circuits by means of which the several types of timing intervals are obtained in controlling the operation of a relay are illustrated in the accompanying drawings, in which:

50 Figure 1 is a diagram of an electrical circuit in which a relay is controlled to-have both a delayed closing operation and a delayed opening operation;

Fig. 2 is a graph showing the operating and resetting time curves for the circuit of Fig. 1;

Fig. 3 is a diagram of an electrical circuit in which a relay is controlled to provide a quick closing or actuating operation, and a slow or delayed opening or resetting operation;

Fig. 4 is a graph showing the operating and resetting time curves for the circuit of Fig. 3;

Fig. 5 is a diagram of an electrical circuit in which a relay is to provide a minimum fixed interval between predetermined successive actuating operations; and

Fig. 6 is a graph showing the relay operating and resetting curves in relation to such time interval and other circuit conditions.

In the diagram shown in Fig. 1, a relay I0 is provided with a winding II and an element 1! controlled thereby that is illustrated, for the purpose of this invention, as a switch, or contact member. The relay is not limited to the control of an electrical circuit switch I2 but may be utilized to operate any mechanical member to perform a mechanical operation. The energization of the relay I0 is derived from a directcurrent supply circuit l3, connected to a direct current source of supply, or through a rectifying device to an alternating current source of supply. For the purpose of this application, however, the energizing circuit I3. is a direct current circuit.

The operation and energization of the relay ill by the direct current energy from the energizing circuit I3 is controlled by two resistors l4 and I5, and a condenser IS. The two resistors are connected in series with the winding H of the relay and the condenser I6 is connected to bridge or shunt the relay winding II and the resistor ii.

In the circuit shown in Fig. 1, the time constants of the resistors I4 and i5, and of the condenser l6, are so co-operatively related to the time constants of the winding ll of the relay ID, that when the circuit I3 is first closed by switch I to energize the relay, the first current charge will be absorbed in charging the condenser l6, so that the energization of the winding of the relay to operate the relay will be delayed. The manner in which the energization of the relay winding is delayed is illustrated in Fig. 2, by the curve 2|, representing the voltage across the relay coil. The relay pick-up value is shown by the horizontal dashed line 22. As the voltage across the relay reaches the value corresponding to the line 22, the relay winding Ii becomes energized to perform its operation to close the switch 12. As will be observed from the graph in Fig, 2, the curve 2| crosses the line 22 at a time T| after the energization of the circuit from the supply l3. That time is a function of the product of the resistance of resistor l4 and the capacitanceof the condenser Hi.

If, now, the relay is to be de-energized to permit the switch |2 to be opened, the circuit I3 is opened by switch and energization of the relay l0 discontinued. The energy magnetically stored in the field of the winding I0 and in the condenser l6 must be dissipated, however, before the winding of the relay will be sufficiently de-energized to permit the relay to return to its initial de-energized position. The respective time constants of the relay winding II and of the resistor l5 and of the condenser 5 are so selected that they will cooperate to provide the time interval that is desired for the de-e'nergization of the winding H of the relay to provide the time delay that is wanted.

Such time delay is illustrated by the curve 25 in Fig. 2, which illustrates the manner in which the current in the circuit of the winding I is slowly dissipated to the drop out value indicated by the horizontal line 23. The time T2 between circuit opening and relay opening is a function of the product of the resistance and capacity constants of resistor I5 and condenser IS.

The circuit shown in Fig. 3 is arranged to provide a quick closing operation and a delayed opening operation of the relay 30. As shown in the drawings, the relay 30 comprises a main holding winding, or coil 3|, and an auxiliary actuating or pick-up coil 32. The construction of the relay is schematically illustrated to show an actuating core 33 that is responsive to the actuating winding 32 and movable thereby to a position at which a holding core 34 will be moved into the holding magnetic zone of the holding winding 3| of the relay. Winding 3| is not sufiiciently strong to actuate the relay, but will hold it in operated closed position once it has been moved thereto by the actuating winding 32. The relay 30, when closed, operates a switch or other similar member 35. The energization of the relay is derived from a direct current circuit 36, through the closureof switch 2 and the timing operations of the relay are controlled by a resistor 31 and a condenser 38. The resistor 31 is connected in series circuit relation between the two windings 3| and 32, and the condenser 38 is connected to bridge or shunt the resistor 31 and the relay holding winding 3|.

When the circuit 36 is'first energized, assuming switch 2 is closed, the immediate charging current impulse to the condenser 38 energizes the actuating winding 32 to actuate the relay to its operated or closed position, at which the holding core 34 is within the range of influence of the holding winding 3|. While as the condenser is charged, the holding winding 3| becomes energized in series with the actuating winding 32 to an extent that is suflicient to hold the relay closed, although it is not sufilcient to close the relay initially from its normally open position. With this circuit, the relay isprovided with a quick closing operation.

When the relay is to be de-energized, the supply circuit 36 is de-energized or switch 2 is opened, and the actuating winding 32 becomes quickly de-energized according to its time constant which must be small. The time constant of the holding winding 3|, however, is comparatively large, and its energy, together with the energy stored in the condenser 38, must be dissipated before the holding winding 3! win be suificiently de-energized to release the holding core 34 to permit the relay to resume its initial open position.

.The closing operation of the relay 30 is quickly effected, as indicated by the charging current 5 curve 4| of Fig. 4, within the time interval T-3. In the meantime, the holding coil is energized, as shown in curve 42, to a value sufiicient to hold the relay closed. When the relay circuit is opened to de-energize the relay, the time curve 10 is illustrated by the curve 43 which represents the decaying current in the circuit of the holding winding. As illustrated, that current does not diminish to the drop-out value until the expiration of an interval T4 after the enerl5 the relay 50 is energized to close its switch 52 25 quickly by reason of the charging current of the condenser 55. The relay then remains closed because of the holding current that then traverses the resistor 54 shunting the condenser 55. The relay 50 will now remain closed as long as circuit 53'is energized or connected to its source. If switch from the energized circuit 53 should now be opened, relay 50 would be de-energized and it would open immediately. The energy stored in the condenser 55, however, must be first dis- 35 sipated in the closed circuit including the condenser 55 and the resistor 54 before a reclosure of the circuit 53 will be able to energize the Winding 5| sufficiently to operate the relay. So long as the condenser 55 remains partially charged, the amount of charging current which it will immediately be able to receive will not be suflicient to re-energize and re-operate the relay 50. The relay will therefore remain insufiiciently energized until the circuit 53 has remained open for a sufiicient time to permit the condenser 55 to discharge or dissipate substantially its entire quantity of stored energy.

The manner in which the circuit in Fig. 5 operates is schematically illustrated by the graph in Fig. 6, in which curve 6| represents the charging current curve when the relay is first connected to the supply circuit 53 after the condenser 55 has become entirely discharged. That current is sufficient to operate the relay. The current through the resistor 54 is shown by curve 62, and the resistance value of resistor 54 in relation to the impedance of coil 5| is so selected that the current through the resistor will be suflicient in magnitude to hold the relay 60 closed. Curve 63 represents the voltage across relay winding 5|.

If now, as at time T5 in Fig. 6, the relay is to be de-energized and the circuit 53 is opened, the

energy of the condenser and resistor combina- 65 to again energize the relay winding 5|. 70

In each case, the condenser and resistor time constants are selected to be co-operatively related to the time constants of the relay in such manner as to provide the operation of the nature described. The selection of such constants will, X

of course, depend upon the design and size of the respective relays and their windings, and upon the operating currents necessary to operate the relay and also upon the value of the drop-out current at which point the relay wili be permitted to open. All of such co-operative relations will follow the well established formulae, applying to inductive and reactive circuits.

By means of such-simple fundamental electrical elements, the time element in the operation of a relay, to its closed position, or to its open position, may be predetermined and controlled in a simple and reliable manner.

My invention is not limited to any specific construction of relays nor to any specific time constants in the elements that are to co-operate with the relays, since the various circuits may be modified withoutdeparting from the spirit and scope of the invention as set forth in the appended claims.

I claim as my invention:

1. A relay system arranged for quick actuation and delayed resetting, comprising a main winding on the relay and an auxiliary winding on therelay, an energizing circuit for the relay,

a condenser in series with the auxiliary winding' and shunting the main winding, and a resistor in circuit with the main winding and the condenser, the time constants of the resistor, 01' the condenser, and of the two relay windings being such that the auxiliary winding will serve to operate the relay, and the main winding will serve to hold the relay in operated position thereafter, but not to actuate the relay to operated position, and such that the main winding will co-operate with the resistor and the condenser to delay the resetting operation of the relay when the relay circuit is de-energized.

2. In combination, a relay comprising an actuating winding and a holding winding connected in series relationship, an energizing circuit therefor, and means connected in parallel to the holding winding and operative when the energizing circuit is energized to effect instantaneous energization of the actuating winding and delayed energization of the holding winding, and operative when the energizing circuit is deenerglzed or opened, to effect instantaneous deenergization of the actuating winding and to efiect delayed de-energization of holding winding.

3. A relay system comprising a relay having an actuating winding and a holding winding, an external resistor connected between the two windings, and a condenser bridging the resistor and the holding winding.

4. In an electric time limit control scheme, in combination, an electromagnetic device having two coils, a condenser, a source of direct current energy, one of said coils and the condenser being connected in series and the other coil being connected in parallel to the condenser, means ior connecting the coils and condenser to said source of direct current energy whereby the coil connected in series with the condenser becomes rapidly energized to thus efiect the operation of the electromagnetic device immediately after connection of said coils and condenser to the said source of direct current and the coil connected across the terminals pi the condenser remains energized by the discharge current of the condenser for a definite time to maintain said electromagnetic device in operated condition for a definite time after the coils and condenser are disconnected from the source of direct current.

RALPH E. MARBURY.

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